Stethos cope



R. E. WEBER Dec. 21, 1965 STETHOS COPE Filed NOV. 19, 1964 FIGZ UnitedStates Patent 3,224,526 STETHOSCOPE Russell E. Weber, Worcester, Mass.,assignor to Cardiosonics Medical Instruments Corporation, Cambridge,Mass, a corporation of Massachusetts Filed Nov. 19, 1964, Ser. No.412,521 8 Claims. (Cl. 181-24) The present invention relates to a newand improved dual receiver stethoscope construction and moreparticularly to a two-microphone stethoscope head having novel andimproved means for selectively connecting one of the two microphones toa sound tube. 7

Dual receiver stethoscope head constructions are well known in the artand frequently have a stem or shaft secured in a body member of the headfor rotation into positions where an opening in the stern selectivelyconnects an apex of one of the microphones with a sound tube engagedwith the stem. Such stethoscope constructions frequently requirerelatively complex and costly means for mounting and rotation of thestem, often involving a series of boring, broaching and reamingmanufacturing steps. In some cases spring locating means are usedexternally of the stem and such means are subject to high stressessometimes shortening the operative life span of the stethoscope headconstructions.

An important object of this invention is to provide a dual microphonemedical stethoscope head construction having relatively easilyconstructed novel means for connecting one of the two microphones to asound tube.

Another object of this invention is to provide a stethoscope headconstruction in accordance with the preceding object which has arelatively long life span and substantially eliminates freezing of thestem and breaking stresses on a spring means incorporated in the stem.

Still another object of this invention is to provide a stethoscope headconstruction in accordance with the preceding objects which contains astop and locating means to both locate the shaft in an operativeposition and urge the shaft into a position where one of the twomicrophones is positively closed off and another of the two microphonesis connected to a sound tube of the stethoscope through a gastightsealed connecting opening which is substantially leakproof.

According to this invention, a stethoscope head construction has a bodymember defining opposed microphones and a substantially centrallylocated cylindrical bore or recess interconnected with the twomicrophones by openings at the apex of each microphone. The microphoneopenings are preferably circular and lie on a coincident axissubstantially normal to an axis of the cylindrical recess. Thecylindrical hollow shaft or stem is snugly and slidably positioned inthe recess and has opposed substantially circular openings lying on anaxis coincident with the axis of the microphone openings in One positionof the stem. A spring means is mounted within the stem with one end ofthe spring means carrying a stop. The spring means resiliently urges thestop partially outwardly of one stern opening to block one microphoneopening while allowing interconnection of a sound tube connected to thestem with a second microphone opening upon selective positioning of thestem. Preferably the stem is secured against axial movement.

In a preferred embodiment of this invention, the spring means comprisesa loaded coil spring having a first end 3,224,526 Patented Dec. 21, 1965surrounding a first stem opening and a second end urging a metallic ballstop partially outwardly of the second opening in the stem to seat inone microphone opening on selective rotation of the stern. It is afeature of this invention that the spring means urges the stop againstthe rim surrounding a first microphone opening and simultaneously urgesa portion of the stern surrounding the second stem opening into tightengagement with a rim portion of the microphone surrounding the secondmicrophone opening to provide a leak proof construction. Surprisingly,even though the spring means surrounds the stem opening, it does notadversely affect sound transfer from a microphone to the sound tube ofthe stethoscope.

These and other features, objects and advantages of the invention willbe better understood and appreciated from the following detaileddescription of one embodiment thereof selected for purposes ofillustration and shown in the accompanying drawing, in which:

FIG. 1 is a top perspective view of a stethoscope head construction inaccordance with this invention; and

FIG. 2 is a cross-sectional view thereof taken through line 22 showing aportion of a sound tube connected to the stethoscope head.

With reference now to the drawing, a metallic stethoscope headconstruction is illustrated generally at 10 in FIG. 1 having aconventional opened bell microphone 11 and an opposed diaphragmmicrophone 12 forming portions of a cylindrical body member 13. Thediaphragm microphone is of conventional construction comprising adiaphragm 14 extending across the mouth of the microphone 12 and securedby a threaded lock ring 15. At the apex of each microphone 11 and 12there is located a circular opening 17 and 18 preferably of equaldiameters and each preferably having a coincident axis. A cylindricalrecess or bore 16 extends through the body member 13 to an end 19 from amouth portion 20. Preferably the cylindrical recess 16 has a singlediameter throughout its axial extent thus rendering its constructionsimple with a single sized drill bit.

A stem 23 is snugly and slidably received within the cylindrical recess16 and has an inner end bearing against the end 19 of the recess 16. Thestem 23 comprises a first tubular cylindrical hollow shaft 24 with anintegral offset angular reduced diameter shaft 25. The shaft portion 25is frictionally engaged with an overlying end of a sound tube 26. Thesound tube 26 preferably comprises a conventional Y-shaped sound tubehaving binaural ear pieces in accordance with known practice in the art.Preferably the axis of shaft 24 is substantially normal to thecoincident axis of openings 17 and 18. Preferably a substantiallyrectangular circular groove 27 is provided on an inner Wall of therecess 16 and a corresponding circular groove 28 is provided on theouter bearing surface of the shaft 24. Grooves 27 and 28 contain a lockring 29 which may be a rubbery O-ring or a metallic ring. The lock ring29 prevents axial movement of the shaft in the recess while allowingrotation of the shaft about its axis.

Shaft 24 has opposed preferably circular openings 30 and 31 preferablyeach having an axis coincident with the axis of microphone openings 17and 18 in the position of the shaft shown in FIG. 2. The diameter ofopening 31 is preferably equal to the diameters of openings 17 and 18.The diameter of opening 30 is preferably greater than the diameter ofopening 31 permitting a cylindrical spring seat to be drilled in theshaft at 33.

A coil spring 32 lies transversely of the shaft 24 wholly within theshaft and has a first end mounted on seat 33 with a second end carryinga stop 34 which is preferably a ball bearing having a spherical surfaceand a diameter such that it is urged against the rim of opening 17 or 18in selected positions of the stem. The diameter of the ball stop ispreferably slightly smaller than the diameter of opening 30 and equal tothe outer diameter of spring 32 allowing these elements to be positionedthrough opening 30. However, the ball stop 34 is snugly surrounded bythe rim of opening 30 thus preventing lateral motion of the stop withrespect to the stem and the microphone. The spherical surface of thesteel ball 34 acts to provide a locating means locating one shaftopening in alignment with one microphone opening while simultaneouslyclosing the other microphone opening. Thus as seen in FIG. 2 thediameter of ball 34 being larger than circular bore 17, the outersurface of the ball is larger than and blocks the opening 17 uponselective rotation of the stem. The coils of the spring 32 are spacedapart when the spring is loaded and in compression so as to allowpassage of sound to the sound tube 26. Surprisingly, even though thecoil spring 32 has an axis coincident with the axis of openings 17, 18,30 and 31, the coils do not detrimentally affect passage of sound from amicrophone to the sound tube.

The operation of the stethoscope head of this invention is extremelysimple. The stem 23 can be rotated by hand from the position shown inFIG. 2 to a position where the diaphragm microphone 12 is closed off orblocked by ball stop 34 and the bell microphone 11 is interconnectedwith the sound tube 26. As the ball 34 slides along the circumferentialpath it may burnish a path within the recess and tend to graduallysmooth the sharp edges normally formed by the drilling of holes 17 and18. When the ball 34 is rotated 180 with the shaft 24 it snaps intoposition in the rim of opening 18 thus closing this opening. Springpressure resiliently urges the rim of the shaft opening 31 against therim of opening 17 in gastight, hermetic relationship to prevent leakagebetween the shaft and the body member at the openings 17 and 31. Thus,the stop 34 acts as a locating means as well as a stop and blockagemeans for closing off one microphone while interconnecting a secondmicrophone.

While the preferred embodiment of this invention has been shown anddescribed, it should be understood that many variations thereof arepossible. For example, while it is preferred to form all parts of thestethoscope head of metal, in some cases the ball stop 34 may beconstructed of plastic or other material and the shape of the stop 34may vary so long as it acts to close one opening upon selectivepositioning. While shaft 24 may have an open inner end as shown, it isalso possible to provide an end cap (not shown) closing the innermostend of the shaft.

In view of the many variations possible within the scope of thisinvention, the present invention is to be limited only by the spirit andscope of the appended claims which follow:

What is claimed is:

1. A stethoscope head construction comprising,

a body member forming diametrically opposed diaphragm and openmicrophones,

said body member having a cylindrical recess symmetrically interposedbetween said microphones, means forming aligned openings from the apexof each of said microphones through said member,

a tubular shaft,

means rotatably securing said shaft within said recess against axialmovement,

means forming an opening through the wall of the shaft adapted onrotation of said shaft to be aligned selectively with either of said twoopenings of said microphones,

and spring means mounted within said shaft and comprising a stop meansfor closing one of said microphone openings upon alignment of anothersaid openings with said shaft opening.

2. A stethoscope head construction comprising,

a body member forming diametrically opposed microphones,

said body member having an elongated cylindrical recess interposedbetween said microphones,

said microphones each having an apex and each defining openings on anaxis substantially normal to the axis of said cylindrical recess,

a cylindrical shaft with means rotatably securing said shaft in saidrecess,

said shaft defining a first and second opening therein with said firstand second shaft openings each being axially aligned with said apexopenings in at least one position of said shaft,

means for selectively closing one of said apex openings mounted withinsaid shaft and comprising a stop member,

said closing means further comprising a resilient spring urging saidstop member outwardly of said shaft and simultaneously urging oneopening of said shaft into gastight relation with an apex opening.

3. A stethoscope head construction in accordance with claim 2 whereinsaid spring is a loaded coil spring having an axis substantiallycoinciding with said apex openings axls.

4. A stethoscope head construction in accordance with claim 2 whereinsaid stop member comprises a spherical surface and said spring is aloaded coil spring having an axis coincident with said axis of saidmicrophone apex openmgs.

5. In a stethoscope head construction having a body member definingopposed microphones,

a cylindrical recess in said body member lying between said microphonesand a stern snugly received in said recess for selectivelyinterconnecting one of said microphones with a sound tube of saidstethoscope head, aligned openings in said body member extending fromsaid recess into said microphones,

the improvement comprising,

said stem comprising a cylindrical hollow shaft having a first openingand a second opening each lying on a common axis normal to the axis ofsaid shaft,

a spring means having a first end mounted within said shaft,

a second end of said spring means carrying a stop,

said spring means resiliently urging said stop partially outwardly ofsaid second opening whereby upon rotation of said stem said stopalternately opens one body opening and simultaneously closes anotherbody opening provided between said microphones.

6. The improvement of claim 5 wherein said spring means comprises a coilspring having an axis coincident with said axis of said openings.

7. A stethoscope head construction comprising,

a body member forming diametrically opposed diaphragm and openmicrophones,

said body member having a cylindrical recess symmetrically interposedbetween said microphones,

means forming aligned openings from the apex of each of said microphonesthrough said member,

a tubular shaft rotatably secured in said recess against axial movement,

said shaft defining openings therein,

said shaft openings being located on said shaft for alignment with saidmicrophone openings,

a coil spring mounted within said shaft having a first end surroundingone of said shaft openings and a second end carrying a stop means urgedtowards said second shaft opening,

said second shaft opening having a diameter larger than the diameters ofsaid microphone openings,

said stop means being resiliently urged against and closing one of saidmicrophone openings while a second 5 6 of said microphone openings isconnected to another a seat located adjacent said one shaft opening forreshaft opening in gastight relationship in a selected talmng sa1d C011p position of rotation of said stem.

References Cited by the Examiner 8. A stethoscope head construction inaccordance With 5 UNITED STATES PATENTS claim 7 and further comprisingsa1d stop means belng a 2,614,646 10/1952 Eaton 181-24 ball, sa1d ballhaving a diameter greater than the diam- 3 035 656 5/1962 Kebel eters ofsaid microphone openings and less than the diameter of said second shaftopening, and LEO SMILOW, Primary Examiner.

1. A STETHOSCOPE HEAD CONSTRUCTION COMPRISING, A BODY MEMBER FORMINGDIAMETRICALLY OPPOSED DIAPHRAGM AND OPEN MICROPHONES, SAID BODY MEMBERHAVING A CYLINDRICAL RECESS SYMMETRICALLY INTERPOSED BETWEEN SAIDMICROPHONES, MEANS FORMING ALIGNED OPENINGS FROM THE APEX OF EACH OFSAID MICROPHONES THROUGH SAID MEMBER, A TUBULAR SHAFT, MEANS ROTATABLYSECURING SAID SHAFT WITHIN SAID RECESS AGAINST AXIAL MOVEMENT, MEANSFORMING AN OPENING THROUGH THE WALL OF THE SHAFT ADAPTED ON ROTATION OFSAID SHAFT TO BE ALIGNED SE-